1. Scope of Invention
This invention is directed to an automotive keyless entry system and more specifically, to an automotive keyless entry system having a unique sensor, preferably including a piezoelectric crystal as a means of actuation.
2. Prior Art
Many keyless entry systems for unlocking automotive vehicles have been disclosed in prior art. U.S. Pat. No. 4,205,325 issued to Haygood et al, describes a system that utilized a computerized keyboard system as a means to enter a digital code. Upon entering the correct digital code, the vehicles electric door lock system would in turn be activated. Additionally, a plurality of other operations could be performed by entering further numerical values. U.S. Pat. No. 4,868,915 issued to Anderson III et al, disclosed a system having a means for defining an interrogation zone, responsive to a coded marker as a means for generating and verifying the correct access code.
Another contribution to the art was disclosed in U.S. Pat. No. 5,134,392 issued to Takeuchi et al, whereas a keyless entry system employed a remote radio code transmitter as a means to activate the vehicles electric lock system.
In U.S. Pat. No. 4,383,242, Sassover teaches an automobile anti-theft system which relies on a hand-held coded transmitter. A tap actuated lock and method of actuating the lock is disclosed by Salem in U.S. Pat. No. 4,197,524. This invention is somewhat closer to the present invention but is distinguished in that a plurality of taps in coded sequence are required to actuate this system and the sensor is of a conventional nature such as an unmodified piezoelectric crystal, a microphone and the like.
Although the above contributions presented significant technological advances in the art, widespread public acceptance has been limited due to the cost of the systems. Also, installing these systems as an aftermarket add-on to the vehicle, presented a task that not only was excessively labor intensive, but if professionally installed has proven too costly for the majority of the motoring public.